The present application is generally related to a device for providing an electrical connection between an implantable pulse generator and one or more stimulation leads.
Neurostimulation systems are devices that generate electrical pulses and deliver the pulses to nerve tissue to treat a variety of disorders. Spinal cord stimulation (SCS) is an example of neurostimulation in which electrical pulses are delivered to nerve tissue in the spine, typically for the purpose of treating chronic pain. While a precise understanding of the interaction between the applied electrical energy and the nervous tissue is not fully appreciated, it is known that application of an electrical field to spinal nervous tissue can effectively mask certain types of pain transmitted from regions of the body associated with the stimulated nerve tissue. Specifically, applying electrical energy to the spinal cord associated with regions of the body afflicted with chronic pain can induce “paresthesia” (a subjective sensation of numbness or tingling) in the afflicted bodily regions. Thereby, paresthesia can effectively mask the transmission of non-acute pain sensations to the brain.
Neurostimulation systems generally include a pulse generator and one or several leads. The pulse generator is typically implemented using a metallic housing that encloses circuitry for generating the electrical pulses. The pulse generator is usually implanted within a subcutaneous pocket created under the skin by a physician. The leads are used to conduct the electrical pulses from the implant site of the pulse generator to the targeted nerve tissue. The leads typically include a lead body of an insulative polymer material with embedded wire conductors extending through the lead body. Electrodes on a distal end of the lead body are coupled to the conductors to deliver the electrical pulses to the nerve tissue.
During an implantation procedure, there can be a relatively large distance between the implant site for the pulse generator and the stimulation site within the epidural space (depending upon the appropriate vertebral level for the patient's chronic pain). The distance may be greater than the length of a commercially available lead. To accommodate such circumstances, “lead extensions” may be employed to provide intermediate electrical connection between the pulse generator and the lead used to deliver stimulation pulses to patient tissue.
A lead extension is quite similar to a stimulation lead in some respects. A lead extension comprises a plurality of terminal electrical contacts on its proximal end that are electrically coupled to conductors within a lead body. Differing from stimulation leads, the distal end of a lead extension comprises a receptacle for providing electrical contacts. Specifically, the receptacle comprises a housing enclosing electrical connectors adapted to couple to the terminals of a stimulation lead. Each respective electrical connector is electrically coupled to a respective wire of the lead body.
Also, it is typical to utilize a somewhat lower durometer polymer for the housing of a lead extension. Specifically, the housing of the lead extension often can be disposed in a subcutaneous location that will apply pressure to the patient when the patient lies on the patient's back. Accordingly, an unduly hard material for the housing could cause a degree of discomfort for the patient.